1. Field of the Invention
This invention relates to a slide rail assembly suitably used to realize a slidable drawer of a cabinet.
2. Prior Art
As illustrated in FIGS. 8 and 9 of the accompanying drawings, a conventional slide rail assembly typically comprises an inner rail a and an outer rail b, having a U-shaped section and lateral rounded edge portions a' and b', a plurality of balls, roller or other revolving objects c . . . being revolvably and serially retained between the pair of juxtaposed rounded edge portions a', b'.
Such a conventional slide rail assembly is normally used by rigidly fitting members d, e respectively to the inner rail a and the outer rail b so that said members become slidable relative to each other. However, a conventional slide rail assembly having a structure as described above is accompanied by certain drawbacks. When such a slide rail assembly is horizontally placed for use in a state as shown in FIG. 8 or under the condition where the rail assembly is placed horizontally but up side down relative to the state shown in FIG. 8, the weight of the fitted member d, and that of the member e are respectively directed in the directions as indicated by arrows f and g. When the weight are so directed, the slide rail assembly can be subjected to a very large load which in turn can cause slipping actions of the inner or outer rail and the revolving objects c . . . or particularly when the assembly is used for a drawer and the distance between the center of the revolving objects c . . . and the inner rail or the outer rail can become uneven, a phenomenon that can bring forth disagreement between the displaced distance of the inner rail a and that of the outer rail b for a drawing action of the drawer and result in unsmooth motion of the drawer.
When a conventional slide rail assembly is to be applied to a side wall of a drawer of a cabinet as illustrated in FIG. 9, the inner rail a is fitted to a member d such as a side wall of the drawer while the outer rail b is fitted to a member e such as a side wall of the encasing cabinet. Since the main body of the inner rail a and that of the outer rail are realized in the form of a plate and the inner rail a and the outer rail b respectively come to a close contact with the members d and e, any vibrating action of the revolving bodies c . . . retained between the inner and outer rails a, b is directly transmitted to the drawer and hence the cabinet and, when the they are made of steel, the vibration can be resonated by them to generate large noises.
3. Problems to be Solved by the Invention
It is therefore an object (the first object) of the present invention, in view of the above described problems, to provide a slide rail assembly comprising not only an inner rail and an outer rail as well as a plurality of revolving objects held between the rounded lateral edges of the rails, wherein the revolving objects and the inner surface of the lateral edges of the the inner and outer rails have an identical radius of curvature, but also one or more than one intermediate revolving object as well as a pair of intermediate revolving objects holding rounded sections provided between the lateral edge portion and on the inside respectively of the inner and outer rails and having a radius of curvature of their inner surfaces identical with that of the revolving objects to be retained therebetween and of the inner surface of the other revolving object retaining portions in order to ensure smooth sliding motion of the assembly and large load bearing capability with a relatively simple construction of the assembly, regardless of the slide rail assembly being used vertically or horizontally.
Another object (the second object) of the invention is to provide a slide rail assembly which is similar to an assembly as described above but has one or more intermediate revolving objects having a radius of curvature which is greater than that of the other revolving objects in order to reduce the speed of revolution of the intermediate revolving objects as compared with that of the other revolving object in order to reduce of wear and hence enhance the durability of the assembly.
Still another object (the third object) of the invention is to provide a slide rail assembly is similar to an assembly as described above whose revolving object holding rounded edge portions squarely face the main bodies of the inner and outer rails so that both the intermediate revolving object holding rounded portions and the revolving object holding edge portions of the inner and outer rails face the direction perpendicular to the main bodies of the inner and outer rails. With such a construction of the slide rail assembly, it becomes highly resistive to a force that tends to pull apart the inner and outer rails in the direction perpendicular to the rail main bodies as well as to a force that tends to push together the inner and outer rails in that direction and hence can ensure smooth sliding motion of the rails.
It is still another object (the fourth object) of the present invention to provide a slide rail assembly which is similar to the one described in reference to the second object but further comprises indentations on both the outer surface of the inner rail and that of the outer rail to form longitudinal grooves in order not only to enhance the strength of the rails but also to provide spaces between the inner and outer rails and the members rigidly fitted thereto with a view to reduce any possible transmission of noises generated by the revolving bodies to the fitted members such as the side wall of a drawer and that of the encasing cabinet.
A further object (the fifth object ) of the invention is to provide a slide rail assembly which is identical with the one described in reference to the fourth object but the spaces formed between the inner and outer rails and the members fitted thereto can be filled with rubber packing and other noise-absorbing materials to enhance the noise-absorbing effect of the spaces and to improve the connection between the rails and the fitted members and hence the rigidity of the assembly.